It's an oft-repeated maxim that one of the reasons that Windows operating systems are plagued by so many viruses, worms, and security exploits is because they are so popular. Extrapolating on this, many have remarked that if Linux, MacOS, or other OSes become more popular, they will attract the attention of virus writers. That may be true, but the increased attention will not necessarily yield the same quantity of viruses and other exploits, says a Register article. Update: Rebuttal article.

>So, in Linux, as long as you've got email addresses in any of
>the files in your /home directory and permission to access
>the SMTP port, the viruses will run just fine.

Workman,

What is going to execute the virus? It always needs a process
to do that. Its more complicated than that..
It is NOT easy to write an email virus for Linux that will
self extract, execute and run, i think its even impossible.

?Say, for example ... what if it were possible to do some
>nasty thing via Mozilla/Firebird extensions?